/*
 * Copyright (c) 1998, 2004, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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package java.beans.beancontext;

import java.util.Iterator;

/**
 * <p>
 * One of the primary functions of a BeanContext is to act a as rendezvous
 * between JavaBeans, and BeanContextServiceProviders.
 * </p>
 * <p>
 * A JavaBean nested within a BeanContext, may ask that BeanContext to
 * provide an instance of a "service", based upon a reference to a Java
 * Class object that represents that service.
 * </p>
 * <p>
 * If such a service has been registered with the context, or one of its
 * nesting context's, in the case where a context delegate to its context
 * to satisfy a service request, then the BeanContextServiceProvider associated with
 * the service is asked to provide an instance of that service.
 * </p>
 * <p>
 * The ServcieProvider may always return the same instance, or it may
 * construct a new instance for each request.
 * </p>
 */

public interface BeanContextServiceProvider {

  /**
   * Invoked by <code>BeanContextServices</code>, this method
   * requests an instance of a
   * service from this <code>BeanContextServiceProvider</code>.
   *
   * @param bcs The <code>BeanContextServices</code> associated with this particular request. This
   * parameter enables the <code>BeanContextServiceProvider</code> to distinguish service requests
   * from multiple sources.
   * @param requestor The object requesting the service
   * @param serviceClass The service requested
   * @param serviceSelector the service dependent parameter for a particular service, or
   * <code>null</code> if not applicable.
   * @return a reference to the requested service
   */
  Object getService(BeanContextServices bcs, Object requestor, Class serviceClass,
      Object serviceSelector);

  /**
   * Invoked by <code>BeanContextServices</code>,
   * this method releases a nested <code>BeanContextChild</code>'s
   * (or any arbitrary object associated with a
   * <code>BeanContextChild</code>) reference to the specified service.
   *
   * @param bcs the <code>BeanContextServices</code> associated with this particular release
   * request
   * @param requestor the object requesting the service to be released
   * @param service the service that is to be released
   */
  public void releaseService(BeanContextServices bcs, Object requestor, Object service);

  /**
   * Invoked by <code>BeanContextServices</code>, this method
   * gets the current service selectors for the specified service.
   * A service selector is a service specific parameter,
   * typical examples of which could include: a
   * parameter to a constructor for the service implementation class,
   * a value for a particular service's property, or a key into a
   * map of existing implementations.
   *
   * @param bcs the <code>BeanContextServices</code> for this request
   * @param serviceClass the specified service
   * @return the current service selectors for the specified serviceClass
   */
  Iterator getCurrentServiceSelectors(BeanContextServices bcs, Class serviceClass);
}
